Method for mold release during glass forming



May 17, 1966 A. E. BRYMER METHOD FOR MOLD RELEASE DURING GLASS FORMINGFiled April 20, 1962 2 Sheets-sheaf. 1

, INVENTOR. flfl ozez/ 5 56/61/68 By 40 MMX 1- Q 912 irrozA/m May 17,1966 BRYMER 3,251,668

METHOD FOR MOLD RELEASE DURING GLASS FORMING Filed April 20, 1962 2Sheets-Sheet 2 INVENTOR. flow-45 flzmme B United States Patent Thisinvention relates to a method and apparatus for forming parisons orpressed glass articles. More particularly, this invention relates to amethod and apparatus for facilitating theremoval of a mold from a glassarticle pressed therein.

In the modern glass forming machines of the press and blow type,production of articles per mold cavity per minute is of the order offrom 20 to 30 articles. It is a requisite that the molds, when strippedfrom the articles, will not adhere to the articles. At increased speedsthis problem becomes more important from the standpoint that the shapedarticle, at the time the mold is stripped therefrom, is relatively hot.With the further increase in forming speeds, the problem will be moreacute.

With the foregoing in mind, it is an object of this invention to providea method of stripping the mold from the formed article by theutilization of an impact force.

It is a further object of this invention to provide an apparatus forimpacting the molds in the stripping direction to insure cleanseparation of the 'mold from the article. v

Other and further objects will be apparent from the followingdescription taken in conjunction with the annexed sheets of drawingswherein:

FIG. 1 is a part sectional elevation through a glass forming unitutilizing the present invention.

FIG. 2 is a sectional elevational view of the forming mold and itssupport.

FIG. 3 is a cross-sectional view taken at line 3--3 on FIG. 2.

The present invention is adapted for use in a glass molding machinewhich may comprise a supporting base, a parison forming mold, a parisontransfer unit and a parison blowing mold, all adapted to work incoordination to produce blown glass articles as illustrated in FIG. 1hereof.

Referring in particular to FIG. 1 there is shown such a glass moldingunit comprising a base 10 supporting a vertically disposed hydrauliccylinder 11 having a piston rod 12 extending therefrom. Mounted on therod 12 is a mold supporting pedestal 13 which has a generally flathorizontal upper surface. A parison mold cage 14- is resiliently mountedto the pedestal 13. The details of this mounting will be described laterwith respect to FIG. 2.

The mold cage 14 carries a parison or shaping mold 15 which is adaptedto be raised into contact with the lower surface of the neck mold 16.The neck mold, in turn, is connected to the under surface of ahorizontal turret 17. The turret 17 is supported at its center by driveshaft 18 which is adapted to rotate the turret to transfer parisonsretained by the neck mold 16 to a partible blow mold 19, which, incombination with the vertically shiftable blow head 20, expands theparison into completed form. The mold charge, which is delivered to themold 15, is pressed therein by the downward move- "ice ment of a plungeror shaping tool 21 which is reciproc-ably mounted within the uppersupport structure 22. The plunger 21 :and mold 15 remain in verticalalignment during the operation of the machine.

- Referring to FIGS. 2 and 3, the manner of mounting the mold cage withrespect to the pedestal is clearly illustrated. The mold cage 14 has aplurality of bolts 23 circumferentially spaced about and threaded intothe bottom thereof. The pedestal 13 has a plurality of cavities 24formed therein within which the heads 25 of bolts 23 are adapted toslide. There are a plurality of cavities 24 equal in number to thenumber of bolts 23. Within each cavity between the bottom surfacethereof and the bolt head 25 is a spring 26 normally under compression,which is adapted to maintain the bolt head 23 seated against the uppershoulders 27 of the cavities 24.

The mold 15 is retained within the mold cage 14 against relativevertical movement so that the mold and cage move as a unit.

As shown in FIG. 1 when the mold 15 and its cage 14 are raised intocontact with the neck mold 16, the

springs 26 will be compressed until the upper surface of the pedestal 13contacts the under surface of the mold cage 14. When in this position,the charge of molten glass within the mold 15 is pressed by the downwardmovement of the plunger 21. With the completion of the pressingoperation, the plunger will be retracted to the position shown in FIG. 1and the hydraulic cylinder 11 will be actuated to lower the pedestal 13.The springs 26 will maintain the mold 15 in contact with the neck moldduring the initial downward movement of the pedestal 13. When thepedestal has been lowered to the extent determined by the length of thebolts 23, the bolt heads 25 will contact the shoulders 27 and the mold15 and its cage 14 will be moved downward, stripping the mold from theparison. Inasmuch as the pedestal 13 is lowered at a relatively constantspeed, the contacting of the heads 25 of the bolts 23 with the shoulders27 will result in the application of an impact force to the cage 14 andthe mold 15. This impact force will result in strip ping the mold 15away from the parison with much less chance of the parison beingdistorted or sticking to the mold 15.

While the invention has been described in connection with a singleparison mold, it should be obvious that the principle of the inventionwould be equally applicable to a forming machine utilizing plural moldcavities.

Furthermore, the basic theory of this invention could be equallyapplicable to the stripping of a plunger, such as that shown in FIG. 1,from the interior of the parison.

As can readily be seen, the movement of a glass cont-acting surface awayfrom the glass, when in a relatively hot and deformable state, shouldadvantageously be as quick and sudden as possible to insure a cleanseparation.

Various modifications may be resorted to within the spirit and scope ofthe appended claims.

is provided with a support, the support being moved at 3 such a rate andspeed that when its movement is terminated an impact force is suddenlyapplied to the mold in the stripping direction thereby to strip the moldfrom the article.

References. Cited by the Examiner UNITED STATES PATENTS Crawford 653 17X Stenhouse 65-231 Clarke 65-361 X Piazzoli 65361 X Senkbeil 65-323Mathias 65322 X DONALL H. SYLVESTER, Primary Examiner.

F. W. MIGA, Assistant Examiner.

1. IN THE METHOD OF FORMING SHAPED GLASS ARTICLES THE IMPROVEMENT WHICHCOMPRISES THE STEPS OF DELIVERING A CHARGE OF MOLTEN GLASS WITHIN AMOLD, MOVING A SHAPING TOOL INTO AND OUT OF THE CHARGED MOLD TO SHAPETHE GLASS ARTICLE, HOLDING A PORTION OF THE ARTICLE STATIONARY ANDAPPLYING AN IMPACT FORCE TO THE MOLD TO INITIATE THE STRIPPING OF THEMOLD FROM THE FORMED ARTICLE.